Multisensory Processing as a Concurrent Contributor to Cognitive and Language Development in School-Aged Children (A Bayesian Approach)

Abstract

Multisensory processing is fundamental to survival of higher animals, humans included. Rapid and successful integration of visual and auditory information in the brain is necessary to ensure comprehensive understanding of the environment and facilitation of motor responses. Indeed, visual and auditory multisensory processing when measured as Motor Reaction Times (MRTs) in adults has long been known to enhance accuracy and speed of responses, though few have considered how development of motor function per se influences age-related increase in multisensory MRTs and contributes to various cognitive abilities, including working memory (WM), intelligence and language development in primary school children. Thus, the current thesis employed a Bayesian approach to meta-analyze literature up to mid- 2023 to test the association between both motor and verbal measures of multisensory processing and WM development, while also showing that multisensory stimuli contributed more significantly to WM capacity than unisensory visual or auditory stimuli alone. The three experimental studies presented in this thesis employed a simple multisensory MRT task, to explore the interaction of motor development and cognitive abilities in children aged 5-10 years. The first study aimed to examine developmental changes in multisensory MRTs, visuomotor responses and non-motor visual Inspection threshold Time tasks in school children to highlight the more significant contributions of age to motor than sensory function. The second study aimed to investigate the development of visual and auditory WM and visually based nonverbal intelligence, and their relationship to multisensory and visuomotor tasks. Our findings demonstrated that age-related performance on nonverbal intelligence and visual rather than auditory WM were the strongest unique predictors of multisensory MRTs. The final study investigated the association between multisensory and visuomotor processing and the development of receptive and expressive vocabulary abilities, and showed that children with faster MRTs in multisensory and visuomotor processing tasks demonstrated higher complex expressive vocabulary scores (as opposed to simple receptive vocabulary). Overall, the findings of this thesis highlight the interaction of motor development and cognitive abilities and demonstrate that simple, fast, and easily accessible assessment measures of multisensory processing, visuomotor coordination, and nonverbal intelligence as measures of both on-going developmental and neurodevelopmental status in school children.